1. Field of the Invention
The present invention relates generally to steering systems for multi-rudder marine vessels, and more particularly to advanced steering system designs which incorporate non-linear tiller arms for rudder control.
2. Description of the Prior Art
Conventional steering and rudder designs for marine vessels, and particularly monohull power boats having two or more rudders, utilize generally straight tiller arms which are linear and parallel with respect to a vessels centerline in a forward cruising mode. The tiller is attached to rudder stock and control movement of the rudder. A hydraulic or ram actuator acts upon and moves one tiller arm, which in turn acts upon and moves the second tiller arm via the tie-bar or mechanical linkage. As the tillers, rudders and linkage assembly are generally rectangularly symmetrical, when the steering system for the boat is used in maneuvering to turn the boat through water, the rudders likewise turn through the same angular displacement, and there is no compensation for different placement of the rudders in starboard and port locations about the hull, nor for differences in hydrodynamic forces acting upon the distinct rudders.
U.S. Pat. No. 7,267,588 issued to Griffiths et al. discloses Selectively Lockable Marine Devices. This steering system includes a mechanical connecting linkage for controlling two separate marine propulsion devices or engines for power boats. First and second actuators are connected to first and second propulsion units to cause them to rotate about their individual axis. The connecting link has two selectable conditions, and can be locked in a stable condition, to cause synchronous rotation or alternatively to allow the units to rotate independently of one another. There is no rudder controls addressed as set forth in Applicants' instant invention for inboard power vessels.
U.S. Pat. No. 4,919,630 issued to Erdberg, is entitled Inboard Drive System For A Marine Craft, and teaches of a conventional drive system for high performance inboard power boats. Multiple propellers and rudders are utilized, along with a T-shaped steering strut assembly projecting outwardly from the rear of the transom. This supports two cooperatively positioned rudder elements secured aft of the respective propellers. The steering strut unit incorporates conventional/straight tiller arms, tie-bar and conventional rectangularly symmetrical design as show in FIG. 4.
U.S. Pat. Nos. 6,415,729; 4,444,145 and 4,082,053 each related to mutli-rudder vessels having different types of linkage assemblies for acting upon the separate rudders in turning maneuvers. None of these references address a system incorporating differential tiller arms of any type.
The prior art, however, fails either alone or in combination with other references, to teach or suggest the Applicants' engineering designs for advanced steering system designs which incorporate non-linear tiller arms for rudder control, nor any similar or related structure, which was designed for creating different turning radii for discrete rudders. In fact, the prior art fails to address this phenomenon as Applicants have, and therefore does not provide the solutions set forth herein. Differential tiller arms are utilized to create distinct angular displacement of the separate rudders in turning maneuvers. The prior art does not disclose or illustrate the mechanical components of the instant invention, and likewise does not address the particular problems Applicants have solved with the described designs.